org.apache.commons.vfs.provider.AbstractOriginatingFileProvider.java Source code

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Here is the source code for org.apache.commons.vfs.provider.AbstractOriginatingFileProvider.java

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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.commons.vfs.provider;

import org.apache.commons.vfs.FileName;
import org.apache.commons.vfs.FileObject;
import org.apache.commons.vfs.FileSystem;
import org.apache.commons.vfs.FileSystemException;
import org.apache.commons.vfs.FileSystemOptions;

/**
 * A {@link FileProvider} that handles physical files, such as the files in a
 * local fs, or on an FTP server.  An originating file system cannot be
 * layered on top of another file system.
 *
 * @author <a href="mailto:adammurdoch@apache.org">Adam Murdoch</a>
 * @version $Revision$ $Date$
 */
public abstract class AbstractOriginatingFileProvider extends AbstractFileProvider {
    public AbstractOriginatingFileProvider() {
        super();
    }

    /**
     * Locates a file object, by absolute URI.
     *
     * @param uri
     */
    public FileObject findFile(final FileObject baseFile, final String uri,
            final FileSystemOptions fileSystemOptions) throws FileSystemException {
        // Parse the URI
        final FileName name;
        try {
            name = parseUri(baseFile != null ? baseFile.getName() : null, uri);
        } catch (FileSystemException exc) {
            throw new FileSystemException("vfs.provider/invalid-absolute-uri.error", uri, exc);
        }

        // Locate the file
        return findFile(name, fileSystemOptions);
    }

    /**
     * Locates a file from its parsed URI.
     */
    protected FileObject findFile(final FileName name, final FileSystemOptions fileSystemOptions)
            throws FileSystemException {
        // Check in the cache for the file system
        final FileName rootName = getContext().getFileSystemManager().resolveName(name, FileName.ROOT_PATH);

        FileSystem fs;
        synchronized (this) {
            fs = findFileSystem(rootName, fileSystemOptions);
            if (fs == null) {
                // Need to create the file system, and cache it
                fs = doCreateFileSystem(rootName, fileSystemOptions);
                addFileSystem(rootName, fs);
            }
        }

        // Locate the file
        // return fs.resolveFile(name.getPath());
        return fs.resolveFile(name);
    }

    /**
     * Creates a {@link FileSystem}.  If the returned FileSystem implements
     * {@link VfsComponent}, it will be initialised.
     *
     * @param rootName The name of the root file of the file system to create.
     */
    protected abstract FileSystem doCreateFileSystem(final FileName rootName,
            final FileSystemOptions fileSystemOptions) throws FileSystemException;
}